The pixel artstyle is super cool, I had a hard time understanding the mechanics, at first I thought I had to press space at the same time as the star became bigger but after some testing I realized that I just need the red circle inside the star. It was a bit difficult at first to get used to the attacking phase, but it did become better once I got the hang of it.
Hp bars under the opponent and the player sword character would be very nice, as sometimes I do damage but I have no idea if my critical or normal hit did enough or how many more hits I need to win.
Also player choosing a debuff when they lose a fight is a nice idea, I do not really know what "spirit means" (I recommend adding a tooltip explaining the stat) but every other stat seemed understandable. It would be nice to also see how much the player has of the current stat. For example when I choose critical damage multiplier I can also see my current critical damage.
I really like the map, feels very "slay the spire" inspired, maybe a cross out (or another visual representation) for the fights that I've completed would be nice